Certain off-road vehicles, such as all-terrain vehicles (ATVs), snowmobiles, construction vehicles and agricultural vehicles to name a few, can be equipped with track assemblies comprising endless tracks that enhance their traction and floatation on soft, slippery, and/or uneven grounds (e.g., soil, mud, sand, ice, snow, etc.) on which they operate.
Typically, a track assembly of such a tracked vehicle comprises a plurality of wheels and an endless track disposed around these wheels. The wheels include a drive wheel to impart motion to the endless track and one or more idler wheels to support part of the vehicle's weight on the ground via the track, guide the track as it is driven by the drive wheel, and/or tension the track.
The wheels of a track assembly are often subject to loads, friction, etc., that can affect their performance, the performance of the endless track, and/or the performance of the track assembly as a whole.
For instance, an idler wheel of the track assembly may be a roller wheel that rolls on an inner side of the track along a bottom run of the track to apply the bottom run of track on the ground. Contact between the roller wheel and a rolling path of the track's inner side may create friction that generates some rolling resistance. Also, in some cases, the endless track's inner side may comprise a plurality of projections, sometimes referred to as “lugs”, which are used to drive and/or guide the track and which may contact the roller wheel as the track is in motion. Contact between the roller wheel and a drive/guide lug creates friction that may be undesirable. For example, in some situations, such friction, if too great, may cause the roller wheel to climb on the drive/guide lug, possibly to a top of the drive/guide lug where the roller wheel may then fall on an opposite lateral side of the drive/guide lug such that the roller wheel is no longer on the rolling path, thereby negatively affecting operation of the track assembly if not render it inoperable altogether. As another example, in some situations, such friction, if too great, may lead to wear of the drive/guide lug and/or the roller wheel at an unacceptable rate. In some circumstances, the roller wheel may also be exposed to hard objects (e.g., rocks, metal pieces, etc.) lying on the ground which may impact and/or get stuck against the roller wheel and inflict abrasive damage. In some cases, the roller wheel may also be exposed to water, snow and/or ice in cold conditions that may cause ice formation on the roller wheel, particular when its surface has been worn so that it includes cracks or the like.
Problems similar to those arising in connection with roller wheels of a track assembly may sometimes also arise in connection with other wheels of the track assembly, such as a front or rear idler wheel or the drive wheel.
Such negative effects may be encountered in various types of tracked vehicles. For example, they may be encountered in ATVs or snowmobiles, which move at relatively high speeds that can worsen such negative effects. Such negative effects may also be encountered in work vehicles, such as agricultural vehicles, construction vehicles, etc., which move at relatively low speeds but bear loads that can worsen such negative effects.
Accordingly, there is a need for improving wheels of a track assembly of a tracked vehicle.